Gonzague Rebetez

University of Bern

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Natalie Banerji

University of Bern

Olivier Bardagot

University of Bern

Priscila Cavassin

University of Bern

Julien Réhault

University of Bern

ΔΤ

Δήμητρα Τσόκκου

University of Bern

Joël Affolter

FHNW University of Applied Sciences and Arts

Iain McCulloch

University of Oxford

Nicolas Leclerc

Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé

Adam Marks

Stanford University

Martin Brinkmann

Université de Strasbourg

Cooperative Institutions

Centre National de la Recherche Scientifique

University of Bern

University of Oxford

Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé

Université de Strasbourg

Institut de Chimie

Northwestern University

King Abdullah University of Science and Technology

Imperial College London

Stanford University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Ultra-high µC* beyond 10 000 F cm-1 V-1 s-1 in organic electrochemical transistors

Research Square (Research Square) (2023)

Olivier Bardagot Pablo Durand Shubhradip Guchait Gonzague Rebetez Priscila Cavassin

Abstract Organic electrochemical transistors (OECTs) are the heart of promising high-sensitivity biosensors, electrophysiological monitors, and neuromorphic devices. In a context of growing interest for such strategic electronics, we investigate a novel PBTTT polymer bearing single ether side chains (PBTTT-8O) in OECTs. Pristine, non-aligned, devices match state-of-the-art transconductance, confirming the value of single ethers for designing next-generation organic mixed ionic-electronic conductors (OMIECs). Moreover, a ten-fold enhancement of 𝜇C*, reaching 12 000 F cm-1 V-1 s-1, is achieved by unidirectional alignment of PBTTT-8O, opening doors to unprecedented device sensitivity. Such improvement is mainly attributed to enhanced hopping along ordered polymer chains, resulting in ultra high mobility over 25 cm2 V-1 s-1. Interestingly, aligned channels dope twice and dedope fifteen times faster than pristine ones, offering a path to achieve rapid ON/OFF device switching. This study reports an easily transferable solution to concomitantly boost the signal amplification and switching speed of bioelectronic devices.

10.21203/rs.3.rs-3221543/v1

Cite

Citations (1)

The effect of residual palladium on the performance of organic electrochemical transistors

Nature Communications (2022)

Sophie Griggs Adam Marks Dilara Meli Gonzague Rebetez Olivier Bardagot

Organic electrochemical transistors are a promising technology for bioelectronic devices, with applications in neuromorphic computing and healthcare. The active component enabling an organic electrochemical transistor is the organic mixed ionic-electronic conductor whose optimization is critical for realizing high-performing devices. In this study, the influence of purity and molecular weight is examined for a p-type polythiophene and an n-type naphthalene diimide-based polymer in improving the performance and safety of organic electrochemical transistors. Our preparative GPC purification reduced the Pd content in the polymers and improved their organic electrochemical transistor mobility by ~60% and 80% for the p- and n-type materials, respectively. These findings demonstrate the paramount importance of removing residual Pd, which was concluded to be more critical than optimization of a polymer's molecular weight, to improve organic electrochemical transistor performance and that there is readily available improvement in performance and stability of many of the reported organic mixed ionic-electronic conductors.

Organic Electronics

Bioelectronics

Organic semiconductor

10.1038/s41467-022-35573-y

Cite

Citations (48)

What Drives the Kinetics and Doping Level in the Electrochemical Reactions of PEDOT:PSS?

Advanced Functional Materials (2021)

Gonzague Rebetez Olivier Bardagot Joël Affolter Julien Réhault Natalie Banerji

Abstract The electrochemical dedoping and redoping processes of a thin poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film immersed in an electrolyte are studied at different temperatures with time‐resolved spectroelectrochemistry in the visible and near‐infrared range. The spectral signatures of neutral, polaronic, and bipolaronic states of PEDOT are resolved using multivariate curve resolution analysis. Kinetic modeling of their dynamics reveals that both the dedoping and redoping are sequential processes and occur within a few hundred milliseconds in the system. Evaluation of the temperature‐dependence with the Van't Hoff, Arrhenius, and Eyring formalisms highlights the role of entropy in both the establishment of the redox equilibrium at a given voltage bias and the reaction rates. This study provides a significant understanding of the fundamental mechanisms determining the level and rate of the electrochemical processes in PEDOT:PSS and will help tailor the design of faster and more efficient bioelectronic devices based on mixed ionic–electronic conductors.

10.1002/adfm.202105821

Cite

Citations (48)

Correction: Bipolarons rule the short-range terahertz conductivity in electrochemically doped P3HT

Materials Horizons (2022)

Δήμητρα Τσόκκου Priscila Cavassin Gonzague Rebetez Natalie Banerji

Correction for ‘Bipolarons rule the short-range terahertz conductivity in electrochemically doped P3HT’ by Demetra Tsokkou et al. , Mater. Horiz. , 2022, DOI: 10.1039/d1mh01343b.

10.1039/d1mh90069b

Cite

Citations (0)

Bipolarons rule the short-range terahertz conductivity in electrochemically doped P3HT

Materials Horizons (2021)

Δήμητρα Τσόκκου Priscila Cavassin Gonzague Rebetez Natalie Banerji

In situ terahertz spectroscopy on electrochemically doped P3HT reveals the impact of polarons and bipolarons on the short-range conductivity.

10.1039/d1mh01343b

Cite

Citations (20)

Gonzague Rebetez Olivier Bardagot Joël Affolter Julien Réhault Natalie Banerji

Source

Cite

Citations (0)

Terahertz conductivity and charge transfer dynamics in electrochemically doped P3HT

Natalie Banerji Δήμητρα Τσόκκου Priscila Cavassin Gonzague Rebetez Olivier Bardagot

Doping of organic semiconductor films enhances their conductivity for applications in organic electronics, thermoelectrics and bioelectronics. However, much remains to be learnt about the properties of the conductive charges in order to optimize the design of the materials. Electrochemical doping is not only the fundamental mechanism in organic electrochemical transistors (OECTs), used in biomedical sensors, but it also represents an ideal playground for fundamental studies. Benefits of investigating doping mechanisms via electrochemistry include controllable doping levels, reversibility and high achievable carrier densities. We introduced here a new technique, applying in-situ terahertz (THz) spectroscopy directly to an electrochemically doped polymer in combination with time-resolved spectro-electrochemistry and chronoamperometry. We evaluate the intrinsic short-range transport properties of the polymer (without the effects of long-range disorder, grain boundaries and contacts), while precisely tuning the doping level via the applied oxidation voltage. We find that polarons and bipolarons need to co-exist in an optimal ratio to reach high THz conductivity for in aqueous KPF6 electrolyte. Moreover, the analysis of the spectro-electrochemistry data shows that those two species are generated at different rates in amorphous and crystalline regions of the film. Overall, the study allows a precise understanding of the electrochemical doping mechanism of the most common semi-crystalline conjugated polymer P3HT.

Bioelectronics

Organic semiconductor

Charge carrier

Organic Electronics

10.1117/12.2628014

Cite

Citations (2)

Absorbance spectra deconvolution and THz spectroscopy: tools to access fundamental mechanisms limiting the development of bioelectronic and energy storage devices

Olivier Bardagot Gonzague Rebetez Priscila Cavassin Julien Réhault Natalie Banerji

Limiting

Absorbance

10.1117/12.2622652

Cite

Citations (0)